--  @testpoint:opengauss关键字characteristics(非保留)，作为函数名
--关键字不带引号-成功
drop function if exists characteristics;
create function characteristics(i integer)
returns integer
as $$
begin
    return i+1;
end;
$$ language plpgsql;
/
--清理环境
drop function characteristics;

--关键字带双引号-成功
drop function if exists "characteristics";
create function "characteristics"(i integer)
returns integer
as $$
begin
    return i+1;
end;
$$ language plpgsql;
/
--清理环境
drop function "characteristics";

--关键字带单引号-合理报错
drop function if exists 'characteristics';
create function 'characteristics'(i integer)
returns integer
as $$
begin
    return i+1;
end;
$$ language plpgsql;
/

--关键字带反引号-合理报错
drop function if exists `characteristics`;
create function `characteristics`(i integer)
returns integer
as $$
begin
    return i+1;
end;
$$ language plpgsql;
/